Introducing Project Wasserboxer 2500E

[SyncroChrick]

it would be so awesome to have a reliable WBX 2.5 available as a replacement...

[boof1306]

Really happy to see your progress. A decent set of p+l is well overdue to this market. I am well over the lack of quality control the qsc's offer. I do hope you are considering using a 22mm gudgeon. There are some very tasty type 1 rods out there just waiting to be used.
Thanks for the shots of the clearancing. I am really surprised they took all that material off the con rod and didn't clearance the cam at all!
Although it is sad you could not get a crank locally I am glad you went with the DPR. Work that good from business that good need to be supported.
Another good thing to do would be to get that cam profiled. The otti cam was great. Greg

[silverbulletuk]

Thanks guys. The cam is on a VAG cast blank and well worn (aren't they always?) but definitely a reprofile as the base circle is down to 30mm dia (not 31mm) and used to have 8.5mm lift on all four lobes.
The front exhaust lobe has now got only 7.6mm lift!!!

I have had some hydro cams made here in the UK to 18/58/58/18 timing (at 1mm lift) and lifting 9.2mm inlet, 8.5 exhaust on standard rockers, but I will mill/grind some relief on them rather than taking the shoulder off the rods.

Still waiting on the 12-off trial batch of 98mm pistons made with standard size pins (but much narrower modern rings) but I can always change this next time around.

The hard bit was sourcing the 2.2mm section O-rings for the 104mm liner spigots, but these are now in hand and the tooling is in the UK, so there is an option to supply spares to other Oetti 2.5 & 3.7 owners.

Now I just have to get to grips with relieving the case to get it all rotating cleanly...
_________________
1986 syncro twin-slider rhd, 3.2S Oettinger wbx6
1990 SA Microbus - Supercharged wbx going in with UN-1 trans.
www.025motorsport.com

[silverbulletuk]

The cam grinders mis-interpreted my written instructions and "thought" that I wanted 18/58/58/18 from first motion... not at 1mm lift as per OEM.
When I came to check the new cams they timed up nothing like either and the inlet and exhaust lift were the same at just over 8mm
So now I have to go and visit them and have the awkward conversation.

Thankfully I have a NOS DJ cam to use as a baseline and reference point for the timing marks (also miles out on the new cams)

So, before I go and commit to a second small batch of cams I would like to ask the considered advice of the experienced engine builders here:

What would you consider to be the most appropriate cam profile/lobe centres/ duration for a wbx in a vanagon, optimised for the following in order of priority:

1st: large capacity stroker efi 98 x 82
2nd: standard 2.1 efi 94 x 76

My gut feeling is still to request 18/58/58/18 @ 1mm lift, 110 lobe centres and cam lift of 9.0 inlet, 8.5 exhaust for use with 1.1 rockers, assuming an improved 4 into 1 exhaust with equal length runners (I like the stainless steel VW Speedshop system available here in UK, it is quiet and well priced if nothing else)

EDIT: Or should I be rethinking my strategy and using 1.25 rockers?

The cam grinders did however manage to achieve the 31mm base circle diameter and I did tell them that the wbx hydraulic lifter is 24mm dia, not bigger as per the aircooled type solid lifter.
_________________
1986 syncro twin-slider rhd, 3.2S Oettinger wbx6
1990 SA Microbus - Supercharged wbx going in with UN-1 trans.
www.025motorsport.com

[boof1306]

Hi Ian, Those kind of figures teamed with a 4-1 will give you an engine that is just coming to life when the rev limiter cuts in. You need to split the grind in my opinion to get a good cam for a WBX. The original grind was 10/48/50/0. I would just increase the exhaust duration a little as you can do so much with the exhaust and run ratio rockers. Maybe

Specifications: (change numbers in red)
Intake open BTC 10
Intake close ABC 48
Exhaust open BBC 54
Exhaust close ATC 4
Calculations: (these numbers calculated)
Intake duration 238
Exhaust duration 238
Intake center 109
Exhaust center 115
Lobe separation 112
Advance 3
Degrees overlap 14

All that said if you just want to build this engine I would throw in that nos dj cam with 1.25 rockers. Greg

[silverbulletuk]

Thanks for the advice, that spec was starting to look a bit racy! I can't think why I had got those timings in my head...

In the event, a visit to the cam manufacturers for a good couple of hours with the NOS DJ cam and the old Oetti 2500E one yeilded the following spec, which I am happy will give good results in a heavy bus:

8.5 cam lift inlet and exhaust, 234 duration @ 1mm lift for both, 110 lobe centres, inlet 1.65mm lift @ tdc, exhaust 1.3 @ tdc, 30mm base circle.

The DJ was 232 inlet, 224 exhaust, 112 lobe centres, only 1.3mm lift @ tdc for the inlet and 1.0mm for the exhaust, 31mm base.
(@1mm it was also short on timing, measuring 4/48/44/0)

So the exhaust timing has been stretched, the inlet only a little, but with more aggressive opening and closing ramps, plus a modest increase in the overlap. The manufacturers were also very careful to make sure that the profile was still within the limits of the 24mm dia wbx lifter, do avoid any gouging of the flanks.

It has ended up being pretty close (as far as we could tell) to the old Oettinger 2.5 cam (itself a reprofiled DJ part), but it was so worn a lot of guesswork was involved there.
_________________
1986 syncro twin-slider rhd, 3.2S Oettinger wbx6
1990 SA Microbus - Supercharged wbx going in with UN-1 trans.
www.025motorsport.com

[silverbulletuk]

Whilst washing out the crankcase I have noticed a curious detail on this Oettinger...
The 8 longest head studs (222mm) have slightly larger diameter shanks than usual!
All of the shorter studs are a nominal 7.5mm (they vary a bit from 7.2 to 7.7) and all are definitely OEM supply from the stamping on the heads, but all of the 222's are 8.5mm

025101143 is the ETKA part number for all of the 222 studs, carried right through from early aircooled, so from where have these heavy ones come?

In addition to that, why use heavier studs? Was it a way of balancing out the stretch between long and short stud in order to get more even clamping on the cylinder heads?
_________________
1986 syncro twin-slider rhd, 3.2S Oettinger wbx6
1990 SA Microbus - Supercharged wbx going in with UN-1 trans.
www.025motorsport.com

[silverbulletuk]

Delays delays... WBX "stretch" conrod bolts have finally gone NLA in Europe, I am hoping it's just a resupply delay because I have some expensive Omega pistons with 24mm pins waiting for a home, along with my NOS Oettinger ones.

Having made a jig to CNC machine the rod cap and pin end of standard rods, I now I have 3 sets of lightened WBX rods waiting for bolts...

I can't go down the ARP BBC route (did a test rod, but it didn't work out) because the bolt heads won't clear the case with an 82mm crank, even with careful clearancing and notches in the roof of the case

The only other route is to cut my losses and buy NOS rods c/w bolts while they are still available.

Another oversight on my part: where to get barrel-to-head seals for 98mm pistons? Oetttinger had specials made to the same design as OEM i.e. a folded/wrapped 4-ply steel laminate, but that's not an option now!

I could get copper shims waterjet cut locally, but off-the-shelf would (I hope) be cheaper.

Any advice gratefully received.
_________________
1986 syncro twin-slider rhd, 3.2S Oettinger wbx6
1990 SA Microbus - Supercharged wbx going in with UN-1 trans.
www.025motorsport.com

[boof1306]

GoWesty used to sell 98mm coppers. They didn't list them but if you email they will process it. That said with postage it might be worth getting them cut. Greg

[caravelle c]

Great project! I hope you can avoid the issues of the original Oettinger WBX 2.5 and WBX6 3.7.

[silverbulletuk]

Please share what you know! My one had 200,000km and still ran well.
I have heard of the 3.7 engines snapping their camshafts?

PS I have had shims quoted at just under £9.00 Sterling each, if I order 24 in 18SWG copper. Not too bad.
_________________
1986 syncro twin-slider rhd, 3.2S Oettinger wbx6
1990 SA Microbus - Supercharged wbx going in with UN-1 trans.
www.025motorsport.com

[caravelle c]

Congrats, you're the first who reached 200000km with a Oettinger 2.5 Most 2.5s need a rebuilt every 50000km. I don't know exactly why, but it has something to do with high oil temperatures and a bore that is to big for the type 1 engine case. And don't forget the German Autobahn, it kills the engine. Both the 3.7 and 2.5 don't like high revs. The 3.2S is better suited for the Autobahn, with a aftermarket camshaft and Megasquirt some reach 190hp.

You can see here more, everything is wafer thin: http://www.bulliforum.com/viewtopic.php?f=1&t=73688&hilit=oettinger+2.5

[silverbulletuk]

Thanks for the link! Information about Oettinger is so hard to find.

I have designed a BIG oil cooler for all wbx, 25row x 235mm with a fan. Not cheap to build, but a blown up engine is much more expensive...

My customer-driven R&D started here http://forum.club8090.co.uk/viewtopic.php?f=12&t=142235&start=15#p8077351

(apologies for the forum cross-links)
_________________
1986 syncro twin-slider rhd, 3.2S Oettinger wbx6
1990 SA Microbus - Supercharged wbx going in with UN-1 trans.
www.025motorsport.com

[silverbulletuk]

I got to drive my customer's Westy syncro the other weekeknd, now that the 2500 has finally been installed.
It really does go quite well, even for an engine that is still loosening up

I would go so far as to say that for a Westy syncro on 215/75/15's and 2-up it has the performance of a healthy 2wd 2.1 DJ bus on standard sized tyres.
It's not underpowered anymore!

I wasn't pushing hard (well one wouldn't...) and the owner of a Suby 2.5 Westy syncro following us commented that we were getting a move on

I hope to get another built soon and get it to my local Tech College for a session on their engine dyno. The same one that McLaren use on occasion
_________________
1986 syncro twin-slider rhd, 3.2S Oettinger wbx6
1990 SA Microbus - Supercharged wbx going in with UN-1 trans.
www.025motorsport.com

[caravelle c]

Ian, here is the right car for your Oettinger 2.5! http://www.thesamba.com/vw/classifieds/detail.php?id=1925849